The present invention relates to automatic performance apparatus, and more particularly to an automatic performance apparatus which can play a chord simultaneously with a melody.
With the progress of digital technologies, some recent electronic musical instruments put into practical use can, not only produce many kinds of tone colors by the single instrument, but also store musical sound information and give an automatic performance.
Such electronic musical instruments include ones which have a performance function called "one-key play". In the electronic musical instrument of this type, in order to store the musical sound information, only the musical scale information of a melody are first stored into a memory by a keyboard operation without considering the lengths of musical notes or a tempo, whereupon the note lengths are added to the scale information by the timings of the operations of a key called "one-key play key". More specifically, at the point of time at which the one-key play key is depressed, the scale information corresponding to one note is read out from the memory. The period of time from this point of time till the next depression of the one-key play key is added to the scale information and stored as the length of the particular note. The musical sound information which includes the musical scale and note lengths thus stored are automatically read out by operating predetermined keys, whereby the automatic performance is executed.
With such conventional automatic performance, however, only the melody is played, which has led to the disadvantage that the performance becomes monotonous as music.
As electronic musical instruments which solve the disadvantage, there have also been put into practical use ones which automatically play an accompaniment, namely, a chord along with the melody. In the electronic musical instrument of this type, the musical sound information of the chord such as the sort, root and length of the chord need to be stored besides the melody. To this end, the prior art has been furnished with separate memories or a single memory which is functionally divided into two sections, so as to store the musical sound information of the melody in one memory (section) and those of the chord in the other memory (section). At the performance, the musical sound information have been successively read out from the respective memories (memory sections), and both the musical sounds have been synchronized and emitted.
With such method, however, since the separate memories (memory sections) are used for the melody and the chord, a circuit for synchronizing both the musical sounds to be read out is indispensable. This has led to the disadvantage of complexity in the arrangement of a read control circuit and also in a read control program.
A further disadvantage is that, due to the memory structure as described above, a large memory area is inevitably unused, so the memory capacity, in effect, becomes unnecessarily large.